Head slider to be adhered to precise positioning actuator, head gimbal assembly with the head slider, method for adhering the head slider to the actuator, manufacturing method of head slider and manufacturing method of head gimbal assembly

ABSTRACT

A head slider provided with at least one head element, to be fixed to an actuator for precisely positioning the at least one head element, includes adhering sections to be adhered to the actuator, and recesses for receiving an adhesive. At least one of the recesses is positioned at each of the adhering sections.

FIELD OF THE INVENTION

[0001] The present invention relates to a head slider to be adhered to aprecise positioning actuator for a head element such as a thin-filmmagnetic head element or an optical head element, to a head gimbalassembly (HGA) with the head slider, to a method for adhering the headslider to the actuator, to a manufacturing method of a head slider andto a manufacturing method of an HGA.

DESCRIPTION OF THE RELATED ART

[0002] In a magnetic disk drive apparatus, thin-film magnetic headelements for writing magnetic information into and/or reading magneticinformation from magnetic disks are in general formed on magnetic headsliders flying in operation above the rotating magnetic disks. Thesliders are supported at top end sections of suspensions of HGAs,respectively.

[0003] Recently, recording and reproducing density along the radialdirection or along the track width direction in the magnetic disk (trackdensity) rapidly increase to satisfy the requirement for ever increasingdata storage capacities and densities in today's magnetic disk driveapparatus. For advancing the track density, the position control of themagnetic head element with respect to the track in the magnetic disk bya voice coil motor (VCM) only has never presented enough accuracy.

[0004] In order to solve this problem, an additional actuator mechanismis mounted at a position nearer to the magnetic head slider than the VCMso as to perform fine precise positioning that cannot be realized by theVCM only. The techniques for realizing precise positioning of themagnetic head are described in for example U.S. Pat. No. 5,745,319 andJapanese patent publication No. 08180623 A.

[0005] As for a precise positioning actuator, there is a piggy-backstructure actuator. This piggy-back structure actuator is formed bypiezoelectric material of PZT in an I-character shape with one endsection to be fixed to a suspension, the other end section to be fixedto a magnetic head slider and a pillar shaped movable arm connectedbetween these end sections. The PZT is driven to perform fine precisepositioning of the magnetic head slider directly attached to thisactuator. On the suspension, stepwise stacked are the actuator and themagnetic head slider, namely, the actuator is caught between thesuspension and the slider to form a stacked cantilever structure.

[0006] However, such piggy-back structure actuator had following variousproblems:

[0007] (1) Because of the stepwise stacked structure, a total thicknessof the HGA around the magnetic head slider increases by the thickness ofthe actuator;

[0008] (2) Since the actuator as a whole consists of piezoelectricmaterial such as PZT of a brittle material, shock resistance is verypoor. Particularly, since the actuator and the magnetic head slider arestacked to form a cantilever structure, a shock easily occurs with amoment and also shock resistance is extremely poor;

[0009] (3) Depending upon the size of the magnetic head slider, a travelof the magnetic head element during the precise positioning operationvaries. Thus, it is difficult to obtain enough stroke;

[0010] (4) Because of three-dimensional and complicated attachmentstructure, the handling at the time of an assembly of the HGA isextremely difficult and it is impossible to use a conventional HGAassembly equipment causing productivity to be very worse; and

[0011] (5) In order not to interfere with the movement of the actuator,it is necessary to assemble with keeping a gap between the actuator andthe magnetic head slider and also between the actuator and thesuspension. However, forming of such gaps will more decrease the shockresistance and it is difficult to precisely keep the gaps constant.Particularly, since it is difficult to keep the suspension, the actuatorand the magnetic head slider in parallel precisely, the headcharacteristics deteriorates.

[0012] To solve the aforementioned various problems, the inventors ofthis application had proposed an actuator provided with a pair ofmovable arms for fixing and catching a head slider in a space betweenthe movable arms (U.S. patent Ser. No. 09/933,774 now pending), and anactuator having the same structure but its main section includingmovable arms being formed by a metal plate (U.S. patent Ser. No.09/972,939 now pending).

[0013] However, in these actuators with the structure for catching sidesurfaces of the head slider in the movable arms, if a space between themovable arms is forcibly widened when adhering the head slider to theactuator, piezoelectric elements formed on the movable arms or at thebase of the movable arms may be damaged. Therefore, it is necessary tofabricate an actuator with a sufficiently larger space between itsmovable arms than a width or a distance between the side surfaces of thehead slider so that an adhesive can be easily entered between the sidesurfaces of the head slider and the movable arms of the actuator.

[0014] However, if the actuator is fabricated to have a sufficientlylarger space between the movable arms than the width of the head slider,following various problems may occur:

[0015] (A) A layer of the adhesive may become too thick causingdeterioration in a resonance characteristics and decrease in stroke;

[0016] (B) Since the adhesive may be restricted at the middle of theadhering surface, an adhesive strength will reduce, a resonancefrequency will be lowered and the stroke will reduce;

[0017] (C) In case an adhesive with a high viscosity is used, theadhesive will not be sufficiently entered between side surfaces of thehead slider and movable arms of the actuator and therefore an enoughstrength in adhering cannot be obtained;

[0018] (D) It is very difficult to control that both spaces between sidesurfaces of the head slider and movable arms of the actuator becomeequal to each other;

[0019] (E) Because the actuator and the head slider are assembled afteran adhesive is coated, the adhesive may squeeze out and deposit to anair bearing surface (ABS) of the head slider and the movable arms of theactuator for example during the assembling causing the control of anamount of the adhesive used to become difficult; and

[0020] (F) Due to the aforementioned problems (A) to (E), variations inadhering strength, in resonance frequency and in stroke characteristicsat the mass production may occur.

SUMMARY OF THE INVENTION

[0021] It is therefore an object of the present invention to provide ahead slider to be adhered to a precise positioning actuator, an HGA withthe head slider, a method for adhering the head slider to the actuator,a manufacturing method of a head slider and a manufacturing method of anHGA, whereby adhering between the actuator and a head slider can beeasily achieved.

[0022] Another object of the present invention is to provide a headslider to be adhered to a precise positioning actuator, an HGA with thehead slider, a method for adhering the head slider to the actuator, amanufacturing method of a head slider and a manufacturing method of anHGA, whereby variations and also deteriorations in adhering strength, inresonance frequency and in stroke characteristics can be decreased.

[0023] According to the present invention, a head slider provided withat least one head element, to be fixed to an actuator for preciselypositioning the at least one head element, includes adhering sections tobe adhered to the actuator, and recesses for receiving an adhesive. Atleast one of the recesses is positioned at each of the adheringsections.

[0024] Since the head slider has the recesses for receiving an adhesive,formed at the adhering sections with the actuator, the adhesives will beentered to the adhering sections with reliability and therefore a stableand sufficient adhering strength can be obtained. Also, as the adhesivewill not squeeze out, an amount of the adhesive used can be preciselycontrolled resulting that variations in adhering strength, in resonancefrequency and in stroke characteristics at the mass production can beprevented from occurring. Furthermore, because a space between theadhering sections of the actuator for catching the head slider can bedetermined to a small value equal to or slightly larger than the widthof the slider, there exists no thick layer of the adhesive and it ispossible to minimize a difference between the right and left gaps at theadhering parts. Therefore, a resonance characteristics and a strokecharacteristics can be prevented from being deteriorated. In addition,because it is possible to apply an adhesive after assembling the headslider with the actuator, the adhering process becomes very easy.

[0025] It is preferred that the at least one recess consists of at leastone groove.

[0026] It is also preferred that the head slider includes an air bearingsurfaces (ABS) and two side surfaces caught and supported by theactuator, and that the at least one groove is formed on each of the twoside surfaces along the ABS.

[0027] It is further preferred that the at least one groove is a grooveformed at an edge between each of the two side surfaces and the ABS.Preferably, the groove is formed along a whole length of the edge.

[0028] Also, it is preferred that the at least one head element is atleast one thin-film magnetic head element.

[0029] According to the present invention, also, an HGA includes a headslider provided with at least one head element, a support member and aprecise positioning actuator fixed to the head slider and to the supportmember for precisely positioning the at least one head element. The headslider includes adhering sections adhered to the actuator, and groovesfor receiving an adhesive. At least one of the grooves is positioned ateach of the adhering sections.

[0030] Since the head slider has at least one groove for receiving anadhesive, at the adhering section with the actuator, the adhesives willbe entered to the adhering section with reliability and therefore astable and sufficient adhering strength can be obtained. Also, as theadhesive will not squeeze out, an amount of the adhesive used can beprecisely controlled resulting that variations in adhering strength, inresonance frequency and in stroke characteristics at the mass productioncan be prevented from occurring. Furthermore, because a space betweenthe adhering sections of the actuator for catching the head slider canbe determined to a small value equal to or slightly larger than thewidth of the slider, there exists no thick layer of the adhesive and itis possible to minimize a difference between the right and left gaps atthe adhering parts. Therefore, a resonance characteristics and a strokecharacteristics can be prevented from being deteriorated. In addition,because it is possible to apply an adhesive after assembling the headslider with the actuator, the adhering process becomes very easy.

[0031] It is preferred that the head slider includes an ABS and two sidesurfaces caught and supported by the actuator, and that the at least onegroove is formed on each of the two side surfaces along the ABS.

[0032] It is also preferred that the at least one groove is a grooveformed at an edge between each of the two side surfaces and the ABS.Preferably, the groove is formed along a whole length of the edge.

[0033] Further, it is preferred that the at least one head element is atleast one thin-film magnetic head element.

[0034] It is preferred that the actuator includes a pair of movablearms, and that the head slider includes two side surfaces caught andsupported by the pair of movable arms of the actuator.

[0035] It is also preferred that a space between the pair of movablearms of the actuator is substantially equal to or slightly larger than adistance between the two side surfaces of the head slider.

[0036] It is further preferred that the actuator further includes a basesection, the pair of movable arms extending forward from the basesection, and that top end sections of the pair of movable arms arecapable of displacing in response to a drive signal applied to theactuator along an ABS of the head slider.

[0037] It is preferred that the pair of movable arms and the basesection of the actuator are made of an elastic sintered ceramic or ametal plate member.

[0038] It is also preferred that each of the pair of movable armsincludes an arm member, and a piezoelectric element formed or adhered ona side surface of the arm member.

[0039] According to the present invention, further, a method foradhering a head slider provided with at least one head element to anactuator for precisely positioning the at least one head elementincludes a step of catching side surfaces of the head slider between apair of movable arms of the actuator, and a step of providing anadhesive into a plurality of grooves. At least one of the plurality ofgrooves is formed on each of the side surfaces of the head slider so asto adhere the side surfaces to the movable arms, respectively.

[0040] After assembling the head slider with the actuator, an adhesiveis entered in at least one groove formed on the side surface of the headslider. Because an adhesive is applied after assembling the head sliderwith the actuator, the adhering process becomes very easy. Also, sincethe adhesive is entered to the adhering section with reliability, astable and sufficient adhering strength can be obtained. Furthermore, asthe adhesive will not squeeze out, an amount of the adhesive used can beprecisely controlled resulting that variations in adhering strength, inresonance frequency and in stroke characteristics at the mass productioncan be prevented from occurring. Furthermore, because an adhesive can beapplied into the grooves, a space between the adhering sections of theactuator for catching the head slider can be determined to a small valueequal to or slightly larger than the width of the slider. Thus, thereexists no thick layer of the adhesive and it is possible to minimize adifference between the right and left gaps at the adhering parts.Therefore, a resonance characteristics and a stroke characteristics canbe prevented from being deteriorated.

[0041] It is preferred that the at least one groove is formed on each ofthe side surfaces along an ABS of the head slider.

[0042] Also, it is preferred that the at least one groove is a grooveformed at an edge between each of the side surfaces and an ABS of thehead slider.

[0043] According to the present invention, still further, amanufacturing method of a head slider includes a step of preparing a barprovided with a plurality of head sliders continuously aligned with eachother, each of the head sliders being provided with at least one headelement, a step of forming blind grooves between the aligned headsliders of the bar, and a step of dicing the bar at a center of eachblind groove by a cutting blade provided with a width narrower than awidth of the blind groove to separate the bar into individual headsliders.

[0044] The groove for receiving an adhesive can be made only by formingthe blind groove on the bar. Thus, it is not necessary to change a barjig for dicing the bar to a new one for making the grooves. Therefore,the conventional manufacturing process can be substantially used, andthe manufacturing process of the magnetic head slider can be preventedfrom complicating.

[0045] It is preferred that the forming step includes a step of formingthe blind grooves from a surface of the bar corresponding to an ABS ofthe head sliders.

[0046] Furthermore, according to the present invention, a manufacturingmethod of an HGA includes a step of forming a head slider provided withat least one head element, side surfaces and a plurality of grooves forreceiving an adhesive, at least one of the grooves being located on eachof the side surfaces, a step of forming an actuator for preciselypositioning the at least one head element, the actuator being providedwith a base section and a pair of movable arms extending from the basesection, the pair of movable arms being capable of displacing inresponse to a drive signal applied to the actuator, a step of catchingside surfaces of the head slider between the pair of movable arms of theactuator, a step of providing an adhesive into the plurality of groovesso as to adhere the side surfaces to the movable arms, respectively, anda step of fixing the base section of the actuator to a support member.

[0047] After assembling the head slider with the actuator, an adhesiveis entered in at least one groove formed on the side surface of the headslider. Because an adhesive is applied after assembling the head sliderwith the actuator, the adhering process becomes very easy. Also, sincethe adhesive is entered to the adhering section with reliability, astable and sufficient adhering strength can be obtained. Furthermore, asthe adhesive will not squeeze out, an amount of the adhesive used can beprecisely controlled resulting that variations in adhering strength, inresonance frequency and in stroke characteristics at the mass productioncan be prevented from occurring. Furthermore, because an adhesive can beapplied into the grooves, a space between the adhering sections of theactuator for catching the head slider can be determined to a small valueequal to or slightly larger than the width of the slider. Thus, thereexists no thick layer of the adhesive and it is possible to minimize adifference between the right and left gaps at the adhering parts.Therefore, a resonance characteristics and a stroke characteristics canbe prevented from being deteriorated.

[0048] It is preferred that the at least one groove is formed on each ofthe side surfaces along an ABS of the head slider.

[0049] It is also preferred that the at least one groove is a grooveformed at an edge between each of the side surfaces and an ABS of thehead slider. Preferably, the groove is formed along a whole length ofthe edge.

[0050] It is further preferred that a space between the pair of movablearms of the actuator is substantially equal to or slightly larger than adistance between the side surfaces of the head slider.

[0051] Further objects and advantages of the present invention will beapparent from the following description of the preferred embodiments ofthe invention as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0052]FIG. 1 is an oblique view schematically illustrating maincomponents of a magnetic disk drive apparatus in a preferred embodimentaccording to the present invention;

[0053]FIG. 2 is an oblique view illustrating the whole structure of anHGA in the embodiment of FIG. 1;

[0054]FIG. 3 is an oblique view illustrating a top end section of theHGA in the embodiment of FIG. 1;

[0055]FIG. 4 is an oblique view illustrating a top end section of theHGA in the embodiment of FIG. 1, seen from a different direction fromFIG. 3;

[0056]FIG. 5 is a plane view illustrating a structure of an actuator inthe embodiment of FIG. 1;

[0057]FIG. 6 is a sectional view illustrating a structure of apiezoelectric element section of the actuator shown in FIG. 5;

[0058]FIG. 7 is an oblique view illustrating an operation of theactuator shown in FIG. 5;

[0059]FIG. 8 is an oblique view illustrating the actuator and a magnetichead slider adhered to the actuator in the embodiment of FIG. 1;

[0060]FIG. 9 is an oblique view illustrating the actuator and a magnetichead slider adhered to the actuator in the embodiment of FIG. 1, seenfrom a different direction from FIG. 8;

[0061]FIG. 10 is an explode oblique view illustrating the actuator and amagnetic head slider adhered to the actuator in the embodiment of FIG.1;

[0062]FIG. 11 is an exploded oblique view illustrating the actuator anda magnetic head slider adhered to the actuator in the embodiment of FIG.1, seen from a different direction from FIG. 10;

[0063]FIG. 12 is an elevation view illustrating the actuator and amagnetic head slider adhered to the actuator in the embodiment of FIG.1, seen from an element-formed surface of a magnetic head slider;

[0064]FIG. 13 is an exploded elevation view illustrating the actuatorand a magnetic head slider adhered to the actuator in the embodiment ofFIG. 1, seen from the element-formed surface of the magnetic headslider;

[0065]FIGS. 14a and 14 b are views illustrating how an actuator and aconventional magnetic head slider with no groove for receiving anadhesive are adhered;

[0066]FIG. 15 is a view illustrating how the actuator and the magnetichead slider in the embodiment of FIG. 1 are adhered;

[0067]FIGS. 16a to 16 f are views illustrating a part of a manufacturingprocess of the magnetic head slider in the embodiment of FIG. 1; and

[0068]FIG. 17 is an oblique view illustrating an actuator and a magnetichead slider adhered to the actuator in another embodiment according tothe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0069]FIG. 1 illustrates main components of a magnetic disk unit of apreferred embodiment according to the present invention, FIG. 2illustrates the whole structure of an HGA in this embodiment, and FIGS.3 and 4 illustrate a top end section of the HGA in this embodiment, seenfrom different directions with each other.

[0070] In FIG. 1, reference numeral 10 denotes a plurality of magnetichard disks rotating around an axis 11, and 12 denotes an assemblycarriage device for positioning each magnetic head element on a track ofeach disk. The assembly carriage device 12 is mainly constituted by acarriage 14 capable of rotating around an axis 13 and a main actuator 15such as for example a voice coil motor (VCM) for driving the carriage 14to rotate.

[0071] Base sections at one ends of a plurality of drive arms 16 stackedalong the axis 13 are attached to the carriage 14, and one or two HGAs17 are mounted on a top section at the other end of each arm 16. Each ofthe HGAs 17 has a slider mounted at its top end section so that theslider opposes to one surface (recording and reproducing surface) ofeach of the magnetic disks 10.

[0072] As shown in FIGS. 2 to 4, the HGA is assembled by fixing a finetracking actuator 22 for precise positioning of a thin-film magnetichead element to a top end section of a suspension 20. Side surfaces of amagnetic head slider 21 provided with a thin-film magnetic head element21 g (FIGS. 8, 10, 12 and 13) are caught in a space between movable armsof the actuator 22.

[0073] A main or course actuator of VCM 15 shown in FIG. 1 is used forrotationally moving the drive arm 16 to which such HGA is attached, soas to move the whole assembly. The actuator 22 contributes the finepositioning of the HGA, which cannot be adjusted by the main or courseactuator 15.

[0074] The suspension 20 is substantially formed, as shown in FIGS. 2 to4, by first and second load beams 23 and 24, a resilient hinge 25coupled with both these first and second load beams 23 and 24, aresilient flexure 26 fixed on the second load beam 24 and the hinge 25,and a circular base plate 27 formed at an attaching section 23 a of thefirst load beam 23.

[0075] The flexure 26 has a flexible tongue 26 a depressed by a dimple(not shown) formed on the second load beam 24 at its one end section. Onthe tongue 26 a, fixed is a base section 22 a of the actuator 22 via aninsulation layer 26 b made of for example polyimide.

[0076] The flexure 26 has elasticity for supporting flexibly themagnetic head slider 21 through the actuator 22 by this tongue 26 a. Theflexure 26 is made of in this embodiment a stainless steel plate (forexample SUS304TA) with a thickness of about 20 μm. The flexure 26 isfixed with the second load beam 24 and with the hinge 25 at a pluralityof points by pinpoint welding.

[0077] The hinge 25 has elasticity providing, to the second load beam24, a force for pressing the magnetic head slider 21 toward thedirection of a magnetic disk surface through the actuator 22 inoperation. The hinge 25 is made of in this embodiment a stainless steelplate with a thickness of about 40 μm.

[0078] The first load beam 23 is made of in this embodiment a stainlesssteel plate with a thickness of about 100 μm, and supports the wholesurface of the hinge 25. The fixing of the first load beam 23 with thehinge 25 is performed by pinpoint welding at a plurality of points.

[0079] The second load bean 24 is also made of in this embodiment astainless steel plate with a thickness of about 100 μn, and fixed to thehinge 25 at its rear end section. The fixing of the second load beam 24with the hinge 25 is performed also by pinpoint welding at a pluralityof points. At a top end of this second load beam 24, formed is alift-tab 24 a for separating the HGA from the magnetic-disk surfaceduring out of operation is prepared.

[0080] The base plate 27 to be attached to the drive arm 16 shown inFIG. 1 is made of in this embodiment a stainless steel or iron platewith a thickness of about 150 μm. This base plate 27 is fixed to theattaching section 23 a of the first load beam 23 by welding.

[0081] On the flexure 26, a flexible conductor member 28 including aplurality of trace conductors of a thin-film multi-layered pattern areformed or disposed. The conductor member 28 is formed by a known methodsimilar to the patterning method of forming a printed circuit board on athin metal plate such as a flexible printed circuit (FPC). For example,the conductor member 28 is formed by sequentially depositing a firstinsulation material layer made of a resin such as polyimide with athickness of about 5 μm, a patterned Cu layer (trace conductor layer)with a thickness of about 4 μm, and a second insulation material layermade of a resin such as polyimide with a thickness of about 5 μm on theflexure 26 in this order. Within the regions of the connection padsformed for connecting with the actuator, the magnetic head element andan external circuit, an Au layer is deposited on the Cu layer and thereis no second insulation material layer on the Au layer.

[0082] In this embodiment, this conductor member 28 consists of a firstconductor member 28 a including two trace conductors connected to themagnetic head element for one side, thus four trace conductors for bothsides, and a second conductor member 28 b including a trace conductorconnected to the actuator 22 for one side, thus two trace conductors forboth sides.

[0083] One end of the trace conductors of the first conductor member 28a is electrically connected to head element connection pads 29 formed onan individually separated and freely movable section 26 c of the flexure26. The connection pads 29 are ball-bonded to terminal electrodes 21 aof the magnetic head slider 21 by Au bonding, wire bonding or stitchbonding. The other end of the trace conductors of the first conductormember 28 a is electrically connected to external circuit connectionpads 30 used for connection with an external circuit.

[0084] One end of trace conductors of the second conductor member 28 bis electrically connected to actuator connection pads 31 formed on aninsulation layer on the tongue 26 a of the flexure 26. The connectionpads 31 are connected to A channel and B channel signal terminals 22 band 22 c formed on the base section 22 a of the actuator 22,respectively. The other end of trace conductors of the second conductormember 28 b is electrically connected to the external circuit connectionpads 30.

[0085] A structure of the HGA according to the present invention is notlimited to the aforementioned structure. Furthermore, although it is notshown, a head drive IC chip may be mounted on a middle of the suspension20.

[0086]FIG. 5 illustrates a structure of the actuator 22 in theembodiment of FIG. 1, FIG. 6 illustrates a structure of a piezoelectricelement section of the actuator 22, and FIG. 7 illustrates operations ofthis actuator 22.

[0087] As will be noted from FIG. 5, the actuator 22 has a rough U-planeshape and consists of a base section 50 (22 a) to be fixed to asuspension and a pair of movable arms 51 and 52 perpendicularlyextending from both side ends of the base section 50. At top endsections of the movable arms 51 and 52, formed respectively are sliderfixing sections 53 and 54 to be fixed to side surfaces 21 b and 21 c ofthe magnetic head slider 21 so that the slider 21 is caught in a spacebetween the slider fixing sections 53 and 54. The spacing between theslider fixing sections 53 and 54 is determined to a value substantiallyequal to or slightly shorter than the width of the magnetic head sliderto be caught therein. A thickness of the actuator 22 is determined to avalue equal to or thinner than that of the magnetic head slider to beheld so that the total thickness of the HGA will not increase due to themounting of the actuator. Conversely, by thickening the actuator 22 upto the thickness of the magnetic head slider to be held, strength of theactuator itself can be increased without increasing the total thicknessof the HGA.

[0088] The slider fixing sections 53 and 54 are projected inwardly,namely toward the magnetic head slider 21, so that only these sections53 and 54 are attached to the side surfaces 21 b and 21 c of themagnetic head slider 21 and that there exists air gaps between theremaining sections of the movable arms 51 and 52 and the side surfacesof the magnetic head slider 21.

[0089] The movable arms 51 and 52 consist of arm members 51 a and 52 aand piezoelectric elements 51 b and 52 b formed on side surfaces of thearm members 51 a and 52 a, respectively.

[0090] The base section 50 and the arm members 51 a and 52 a of theactuator 22 are united by an elastic sintered ceramic such as ZrO₂ forexample. Since the main sections of the actuator are made of the elasticsintered ceramic such as ZrO₂ that is strong for bending, a shockresistance of the actuator itself increases.

[0091] Each of the piezoelectric elements 51 b and 52 b has, as shown inFIG. 6, a multi-layered structure of alternately laminatingpiezoelectric material layers 60, signal electrode layers 61 and ground(common) electrode layers 62. By applying voltage across the signalelectrode layers 61 and the ground (common) layers 62, the piezoelectricmaterial layers 60 expand and contract. The piezoelectric material layer60 is made of material that expands and contracts by reversepiezoelectric effect or by electrostrictive effect. The signal electrodelayers 61 are electrically connected to the A channel signal terminal 22b or the B channel signal terminal 22 c, and the ground (common)electrode layers 62 are electrically connected to ground (common)terminal 22 d or 22 e, shown in FIGS. 3 and 4.

[0092] In case that the layers 60 are made of piezoelectric materialsuch as PZT (Lead Zirconate Titanate Oxidization), these piezoelectricmaterial layers are in general polarized so as to improve theirdisplacement performance. The polarized direction is the laminationdirection of the piezoelectric material layers 60. When voltage isapplied across the electrode layers and the direction of the producedelectrical field is the same as the polarized direction, thepiezoelectric material layer between the electrode layers expands in itslamination direction (piezoelectric longitudinal effect) and contractsin its in-plane direction (piezoelectric lateral effect). Contrary tothis, when the direction of the produced electrical field is in inverseas the polarized direction, the piezoelectric material layer between theelectrode layers contracts in its lamination direction (piezoelectriclongitudinal effect) and expands in its in-plane direction(piezoelectric lateral effect).

[0093] If the voltage with a polarity which will induce the contractionor expansion is applied to the piezoelectric element 51 b and 52 b, thepiezoelectric element contracts or expands in response to the appliedvoltage polarity and thus the movable arms 51 and 52 bend to trace aS-character resulting the top end sections of the arms 51 and 52 tolaterally and linearly displace as shown in FIG. 7. Thus, the magnetichead slider 21 fixed with the actuator 22 also laterally and linearlydisplaces. Since the slider displaces namely oscillates with linearmotion not swinging or rotational motion, more precise positioning ofthe magnetic head element can be expected.

[0094] It is possible to apply voltages that induce mutually reversemotions may be simultaneously applied to the piezoelectric elements 51 band 52 b, respectively. In other words, AC voltages may besimultaneously applied to the piezoelectric elements 51 b and 52 b sothat one piezoelectric element expands when the other piezoelectricelement contracts and vice versa. The oscillation of the movable arms iscentered when no voltage is applied to the piezoelectric elements. Inthis case, the amplitude of the oscillation will be about twice of thatwhen the AC voltages are applied.

[0095] However, one of the piezoelectric elements is expanded andtherefore the direction of the driving voltage opposes to that of thepolarization in the piezoelectric material layer. Thus, if the appliedvoltage is high or the voltage is continuously applied, attenuation inpolarization of the piezoelectric material layer may occur. It isdesired therefore that a constant DC bias voltage in the same directionas the polarization direction be additionally applied to the AC voltageto form the driving voltage so that the direction of the driving voltagenever opposes to that of the polarization in the piezoelectric materiallayer. The oscillation of the movable arms is centered when only thebias voltage is applied to the piezoelectric elements.

[0096] In this specification, the piezoelectric material is materialthat expands or contracts by their reverse piezoelectric effect orelectrostrictive effect. Any piezoelectric material applicable for thepiezoelectric elements of the actuator can be used. However, for highrigidity, it is desired to use a ceramics piezoelectric material such asPZT[Pb(Zr,Ti)O₃], PT(PbTiO₃), PLZT[(Pb,La)(Zr,Ti)O₃], or barium titanate(BaTiO₃).

[0097] Each of the piezoelectric elements may have a single layerstructure of alternately laminating a piezoelectric material layer, asignal electrode layer and a ground (common) electrode layer.

[0098] As aforementioned, since the actuator 22 in this embodiment holdsthe side surfaces of the magnetic head slider 21 so that the slider 21is caught in a space between the movable arms 51 and 52, the thicknessof the HGA around the magnetic head slider does not increase even if theactuator 22 is attached. Thus, no modifications in size of the magneticdisk drive apparatus due to the mounting of the actuator is necessary.Also, since the actuator 22 and the magnetic head slider 21 are notstacked to form a cantilever structure, a shock resistance can begreatly improve. Furthermore, since the magnetic head slider 21 iscaught in between the movable arms 51 and 52, the top end sections ofthe movable arms 51 and 52, which actually transfer the displacement tothe slider 21, can be always positioned at the top end of the slider 21.Thus, it is possible to provide a constant travel to the slider even ifthe size of the magnetic head slider 21 changes, and therefore an enoughstroke of the magnetic head at the precise positioning operation can bealways obtained.

[0099] According to the present invention, the magnetic head slider 21is designed to have at least one recess at each of the side surfaces 21b and 21 c, for receiving an adhesive used to adhere the magnetic headslider to the actuator 22. Hereinafter, the configuration or shape ofthe slider 21 will be described in detail.

[0100]FIGS. 8 and 9 illustrate the actuator 22 and a magnetic headslider 21 adhered to the actuator 22 in this embodiment, seen fromdifferent directions with each other, FIGS. 10 and 11 illustrate theactuator 22 and the magnetic head slider 21 in this embodiment, seenfrom different directions with each other, and FIGS. 12 and 13illustrate the actuator 22 and the magnetic head slider 21 adhered tothe actuator 22 in this embodiment, seen from an element-formed surfaceof the magnetic head slider.

[0101] As will be noted from these figures and FIGS. 1-5 and 7, themagnetic head slider 21 has a substantially rectangular parallelepipedshape with an ABS 21 d, a surface 21 e opposite to the ABS, the sidesurfaces 21 b and 21 c, a top end surface 21 f and a rear end surface oran element-formed surface 21 h on which the thin-film magnetic headelement 21 g and the terminal electrodes 21 a are formed. Particularly,in this embodiment, the magnetic head slider 21 has grooves 21 i and 21j formed at ABS side edges of the side surfaces 21 b and 21 c alongtheir whole length, respectively. These grooves 21 i and 21 j receive anadhesive used to adhere the magnetic head slider 21 to the slider fixingsections 53 and 54 of the actuator 22. Due to providing the grooves 21 iand 21 j at the side surfaces 21 b and 21 c, following variousadvantages can be expected.

[0102]FIGS. 14a and 14 b illustrate how an actuator and a conventionalmagnetic head slider 21′ with no groove for receiving an adhesive areadhered, and FIG. 15 illustrates how the actuator 22 and the magnetichead slider 21 in this embodiment are adhered.

[0103] As shown in FIG. 14a, when the conventional magnetic head slider21′ is adhered to the actuator, it is necessary that a space between theslider fixing sections 53′ and 54′ of the actuator is a sufficientlylarger than the width of the slider 21′. Therefore, it is very difficultto control that right and left gaps 140 and 141 between side surfaces ofthe magnetic head slider 21′ and the slider fixing sections 53′ and 54′of the actuator become equal to each other. Also, a layer of theadhesive may become too thick causing deterioration in a resonancecharacteristics and decrease in stroke. Furthermore, as shown in FIG.14b, since a restriction 142 of the adhesive may be formed at the middleof each adhering surface, an adhesive strength will reduce, a resonancefrequency will be lowered and the stroke will reduce. In addition, if anadhesive with a high viscosity is used, the adhesive will not besufficiently entered between side surfaces of the magnetic head sliderand the slider fixing sections of the actuator and therefore an enoughstrength in adhering cannot be obtained. Also, as shown in FIG. 14b,because the actuator and the magnetic head slider 21′ are assembledafter an adhesive is coated, the adhesive may squeeze out and thus anadhesive deposition 143 to an ABS of the magnetic head slider and anadhesive deposition 144 to the bottom surfaces of the actuator and theslider may occur. Therefore, the control of an amount of the adhesiveused to become very difficult. Due to these problems, variations inadhering strength, in resonance frequency and in stroke characteristicsat the mass production may occur.

[0104] Contrary to this, according to this embodiment, as shown in FIG.15, since the magnetic head slider 21 has the grooves 21 i and 21 j forreceiving adhesives 150 and 151, formed at its respective side surfaces21 b and 21 c, the adhesives will be entered to the adhering partsbetween the actuator 22 and the magnetic head slider 21 with reliabilityand therefore a stable and sufficient adhering strength can be obtained.Also, as the adhesive will not squeeze out, an amount of the adhesiveused can be precisely controlled resulting that variations in adheringstrength, in resonance frequency and in stroke characteristics at themass production can be prevented from occurring. Furthermore, because aspace between the slider fixing sections 53 and 54 of the actuator 22for catching the magnetic head slider 21 can be determined to a smallvalue equal to or slightly larger than the width of the slider 21, thereexists no thick layer of the adhesive and it is possible to minimize adifference between the right and left gaps at the adhering parts.Therefore, a resonance characteristics and a stroke characteristics canbe prevented from being deteriorated. In addition, because it ispossible to apply an adhesive after assembling the magnetic head slider21 with the actuator 22, the adhering process becomes very easy.

[0105] In the aforementioned embodiment, the grooves 21 i and 21 j areformed at the ABS-side edges of the side surfaces 21 b and 21 c alongtheir whole length. However, in modifications, these grooves may beformed along only a partial length of the ABS-side edges correspondingto the adhering parts, namely corresponding to the slider fixingsections 53 and 54 of the actuator 22. In modifications, also, a recesswith other shape may be formed instead of the groove. Furthermore, aplurality of grooves or recesses may be formed at each ABS-side edge ofthe magnetic head slider.

[0106]FIGS. 16a-16 f illustrate parts of a manufacturing process of themagnetic head slider in this embodiment.

[0107] First, a plurality of bars are obtained by dicing an wafer onwhich many of magnetic head elements have been formed in matrix by athin-film fabrication method. As shown in FIG. 16a, each bar 160 has aplurality of continuously aligned magnetic head sliders with themagnetic head elements 161.

[0108] Then, as shown in FIG. 16b, by means of a grinding wheel 162, afirst grooving work of the bar 160 from the ABS side is performed. Thisfirst grooving work should be completed before the grinding wheel 162comes through the bar 160 as shown in FIG. 16c. Thus, blind grooves 163each having a concave contour corresponding to a shape of a blade edgeof the grinding wheel 162 are formed.

[0109] Thereafter, as shown in FIG. 16d, a second grinding work forgrooving the center of each blind groove 163 is executed to dice the bar160 by means of a grinding wheel 164 with a narrower width than that ofthe blind groove 163. Thus, as shown in FIGS. 16e and 16 f, individuallyseparated magnetic head sliders 165 are obtained.

[0110] As will be seen from FIGS. 16e and 16 f, each magnetic headslider 165 has grooves 166 at the ABS-side edges of the both sidesurfaces along the whole length of the ABS-side edges.

[0111] As aforementioned, according to this embodiment, the grooves 166for receiving an adhesive can be made only by forming the blind grooves163 on the bar 160. Thus, it is not necessary to change a bar jig fordicing the bar 160 to a new one for making the grooves. Therefore, theconventional manufacturing process can be substantially used, and themanufacturing process of the magnetic head slider can be prevented fromcomplicating.

[0112]FIG. 17 illustrates an actuator and a magnetic head slider adheredto the actuator in another embodiment according to the presentinvention.

[0113] In this embodiment, a configuration of the magnetic head slider21 is the same as that in the embodiment of FIG. 1.

[0114] However, in this embodiment, a main section of an actuator 22′ isformed by cutting a metal plate into individual actuator members eachhaving a rough U-plane shape and by bending each of them in athree-dimensional shape. Namely, the actuator member is bent at bothside ends of its plane base section 170 toward almost perpendiculardirection. A pair of movable arms 171 and 172 that are kept in almostperpendicular to the base section 170 extend frontward from these bentareas. The upper surface, in the figure, of the base section 170 isfixed to the suspension. The movable arms 171 and 172 are formed in aplane shape parallel to the side surfaces of the magnetic head slider21.

[0115] At top end sections of the movable arms 171 and 172, formedrespectively are slider fixing sections 173 and 174 to be fixed to theside surfaces of the magnetic head slider 21 by bending the armsinwardly in a crank arm shape. The spacing between the slider fixingsections 173 and 174 is determined to a value substantially equal to orslightly larger than the width of the magnetic head slider to be caughttherein. The slider fixing sections 173 and 174 are bent inwardly toproject toward the side surfaces of the magnetic head slider 21, so thatonly these sections 173 and 174 are attached to the side surfaces of themagnetic head slider 21 and that there exists air gaps between theremaining sections of the movable arms 171 and 172 and the side surfacesof the magnetic head slider 21.

[0116] The movable arms 171 and 172 consist of arm members (171 a) andpiezoelectric elements (171 b) formed on side surfaces of the armmembers, respectively.

[0117] The base section 170 and the arm members of the actuator 22′ areunited and formed by bending an elastic single metal plate such as astainless steel plate for example. Since the main section of theactuator is of the metal plate, a weight of the actuator decreases andalso a shock resistance of the actuator itself increases. Instead of asteel alloy spring plate such as the stainless steel plate, a resilientplate spring member for example a carbon steel spring plate, a copperalloy spring plate such as copper titanium plate, a phosphor bronzeplate or a beryllium copper plate, or a titanium plate may be used. Incase that the piezoelectric elements are formed by printing andsintering, it is necessary to use a high heat resistance metal plate.

[0118] As aforementioned, since the main section of the actuator 22′ inthis embodiment are made from a metal plate, the weight of the wholeactuator can be reduced and thus a mechanical resonance frequency of theactuator can be increased. Also, as the basic member is formed by themetal plate that is strong and light-weighted, a shock resistance of themovable arms 171 and 172 which are particularly weaken for the shock canbe greatly improved. Due to the usage of the metal plate provided with ahigh mechanical strength, treatment of the actuator during assembling ofthe HGA becomes very easy.

[0119] By using the metal plate to form the main section of theactuator, the flexibility on a design of the actuator will improve withthe shape and/or size. Thus, not only it is enabled to design theactuator with a sufficient stroke, but also it is possible to align thecenter of the magnetic head slider 21 and the load point or dimpleposition with the center of the actuator 22′ resulting the flyingperformance of the magnetic head slider 21 to be extremely stabilized.Because the metal plate can be precisely machined, accuracy in size ofthe actuator 22′ itself can be greatly improved.

[0120] Furthermore, since the actuator 22′ in this embodiment holds theside surfaces of the magnetic head slider 21 so that the slider 21 iscaught in a space between the movable arms 171 and 172, the thickness ofthe HGA around the magnetic head slider does not increase even if theactuator 22′ is attached. Thus, no modifications in size of the magneticdisk drive apparatus due to the mounting of the actuator is necessary.

[0121] In addition, since the actuator 22′ and the magnetic head slider21 are not stacked to form a cantilever structure, a shock resistancecan be greatly improved.

[0122] Further, since the magnetic head slider 21 is caught in betweenthe movable arms 171 and 172, the top end sections of the movable arms171 and 172, which actually transfer the displacement to the slider 21,can be extended to always position at the top end of the slider 21.Thus, it is possible to provide a constant travel to the slider even ifthe size of the magnetic head slider 21 changes, and therefore an enoughstroke of the magnetic head at the precise positioning operation can bealways obtained.

[0123] Other configurations such as forming of grooves for receiving anadhesive on the magnetic head slider 21, operations, advantages andmodifications in this embodiment are the same as those in theembodiments of FIG. 1. Also, in FIG. 17 of this embodiment, the similarelements as those in the embodiment of FIG. 1 are represented by thesame reference numerals.

[0124] In the aforementioned embodiments, the precise positioningactuators for the thin-film magnetic head elements and the HGAs with theactuators are described. However, it is apparent that the presentinvention can be applied to a precise positioning actuator for a headelement such as an optical head element other than the thin-filmmagnetic head element and an HGA with the actuator.

[0125] Many widely different embodiments of the present invention may beconstructed without departing from the spirit and scope of the presentinvention. It should be understood that the present invention is notlimited to the specific embodiments described in the specification,except as defined in the appended claims.

What is claimed is:
 1. A head slider provided with at least one head element, to be fixed to an actuator for precisely positioning said at least one head element, said head slider comprising: adhering sections to be adhered to said actuator; and recesses for receiving an adhesive, at least one of said recesses being positioned at each of said adhering sections.
 2. The head slider as claimed in claim 1, wherein said at least one recess consists of at least one groove.
 3. The head slider as claimed in claim 2, wherein said head slider comprises an air bearing surfaces and two side surfaces caught and supported by said actuator, and wherein said at least one groove is formed on each of said two side surfaces along said air bearing surface.
 4. The head slider as claimed in claim 3, wherein said at least one groove is a groove formed at an edge between each of said two side surfaces and said air bearing surface.
 5. The head slider as claimed in claim 4, wherein said groove is formed along a whole length of said edge.
 6. The head slider as claimed in claim 1, wherein said at least one head element is at least one thin-film magnetic head element.
 7. A head gimbal assembly including a head slider provided with at least one head element, a support member and a precise positioning actuator fixed to said head slider and to said support member for precisely positioning said at least one head element, said head slider comprising: adhering sections adhered to said actuator; and grooves for receiving an adhesive, at least one of said grooves being positioned at each of said adhering sections.
 8. The head gimbal assembly as claimed in claim 7, wherein said head slider comprises an air bearing surfaces and two side surfaces caught and supported by said actuator, and wherein said at least one groove is formed on each of said two side surfaces along said air bearing surface.
 9. The head gimbal assembly as claimed in claim 8, wherein said at least one groove is a groove formed at an edge between each of said two side surfaces and said air bearing surface.
 10. The head gimbal assembly as claimed in claim 9, wherein said groove is formed along a whole length of said edge.
 11. The head gimbal assembly as claimed in claim 7, wherein said at least one head element is at least one thin-film magnetic head element.
 12. The head gimbal assembly as claimed in claim 7, wherein said actuator comprises a pair of movable arms, and wherein said head slider comprises two side surfaces caught and supported by said pair of movable arms of said actuator.
 13. The head gimbal assembly as claimed in claim 12, wherein a space between said pair of movable arms of said actuator is substantially equal to or slightly larger than a distance between said two side surfaces of said head slider.
 14. The head gimbal assembly as claimed in claim 12, wherein said actuator further comprises a base section, said pair of movable arms extending forward from said base section, and wherein top end sections of said pair of movable arms are capable of displacing in response to a drive signal applied to said actuator along an air bearing surface of said head slider.
 15. The head gimbal assembly as clamed in claim 14, wherein said pair of movable arms and said base section of said actuator are made of an elastic sintered ceramic.
 16. The head gimbal assembly as claimed in claim 14, wherein said pair of movable arms and said base section of said actuator are made of a metal plate member.
 17. The head gimbal assembly as clamed in claim 12, wherein each of said pair of movable arms comprises an arm member, and a piezoelectric element formed or adhered on a side surface of said arm member.
 18. A method for adhering a head slider provided with at least one head element to an actuator for precisely positioning said at least one head element, said method comprising the steps of: catching side surfaces of said head slider between a pair of movable arms of said actuator; and providing an adhesive into a plurality of grooves, at least one of said plurality of grooves being formed on each of said side surfaces of said head slider so as to adhere said side surfaces to said movable arms, respectively.
 19. The method as claimed in claim 18, wherein said at least one groove is formed on each of said side surfaces along an air bearing surface of said head slider.
 20. The method as claimed in claim 18, wherein said at least one groove is a groove formed at an edge between each of said side surfaces and an air bearing surface of said head slider.
 21. A manufacturing method of a head slider comprising the steps of: preparing a bar provided with a plurality of head sliders continuously aligned with each other, each of said head sliders being provided with at least one head element; forming blind grooves between said aligned head sliders of said bar; and dicing said bar at a center of each blind groove by a cutting blade provided with a width narrower than a width of said blind groove to separate said bar into individual head sliders.
 22. The method as clad in claim 21, wherein said forming step comprises a step of forming the blind grooves from a surface of said bar corresponding to an air bearing surface of the head sliders.
 23. A manufacturing method of a head gimbal assembly comprising the steps of: forming a head slider provided with at least one head element, side surfaces and a plurality of grooves for receiving an adhesive, at least one of said grooves being located on each of said side surfaces; forming an actuator for precisely positioning said at least one head element, said actuator being provided with a base section and a pair of movable arms extending from said base section, said pair of movable arms being capable of displacing in response to a drive signal applied to said actuator; catching side surfaces of said head slider between said pair of movable arms of said actuator; providing an adhesive into said plurality of grooves so as to adhere said side surfaces to said movable arms, respectively; and fixing said base section of said actuator to a support member.
 24. The method as claimed in claim 23, wherein said at least one groove is formed on each of said side surfaces along an air bearing surface of said head slider.
 25. The method as claimed in claim 23, wherein said at least one groove is a groove formed at an edge between each of said side surfaces and an air bearing surface of said head slider.
 26. The method as claim in claim 25, wherein said groove is formed along a whole length of said edge.
 27. The method as claimed in claim 23, wherein a space between said pair of movable arms of said actuator is substantially equal to or slightly larger than a distance between said side surfaces of said head slider. 